- Patients must not have taken oral or inhaled anti-inflammatory agents, including ICS and leukotriene inhibitors, for at least one month prior to study entry; and anti-IgE medications at least the past six months. Documented use of inhaled short-acting or long-acting β2-agonists during the month prior to study entry is, however, required. Xanthines, long-acting anticholinergics, and long-acting β2-agonists must be withdrawn within 72 hours upon entering the screening phase; short acting anticholinergics must be withdrawn within 48 hours before entering the screening phase. Patients will be required to abstain from these medications for the duration of study participation.